The number "2006" in your search refers to the year the standard was published.
| Feature | 70-2006 | 70-2020 (Updated) | | :--- | :--- | :--- | | | HCFCs, HFCs, NH3 (Ammonia) | Added A2L (mildly flammable) and A3 (highly flammable) refrigerants like R-32, R-454B, and propane (R-290). | | Test Uncertainty | +/- 5% allowed | +/- 3% for critical flow; added rigorous uncertainty analysis protocol. | | Instrument Calibration | Annual calibration suggested | Mandatory traceable calibration to NIST every 6 months. | | Backpressure Correction | Simplified method | New complex correction factors for valves with built-in backpressure compensation. | | Reporting | Basic data sheet | Mandatory electronic data logging with a minimum 1 second sampling rate. | ashrae standard 702006 pdf updated
For professional use, ASHRAE standards are typically purchased as protected PDF files. The number "2006" in your search refers to
The 2023 update introduces several critical improvements over the 2006 version to better align with modern HVAC technology: | | Instrument Calibration | Annual calibration suggested